The present invention relates to a system of authentication, device, program, and method, which can be applied to various authentication systems.
In general, upon authenticating each other's devices connected via a network, digital authentication using a public key cipher techniques based on public-key cryptosystems and challenge & response technique is prevalent.
In such digital authentication, a prover can show his or her own authenticity by an arithmetic process of numerical values given by a verifier, and the verifier can verify the authenticity of the prover by an arithmetic process and comparison process of the numerical values received from the prover.
Hence, such digital authentication is a technique suited to partner authentication used to identify a partner, as in electronic transactions and normal access control.
The conventional digital authentication is suitable for normal partner authentication used to identify a partner. However, according to considerations by the present inventors, the conventional digital authentication may be unsuitable for a case wherein other people's devices are operated as idle resources by collaboration, which is a recent trend in ubiquitous networking of information communication devices. Note that “ubiquitous” means existing or being everywhere.
The reason why the conventional digital authentication is unsuitable is that the conventional digital authentication makes an alternative decision of “authentic” or “unauthentic”. For example, in a ubiquitous network, many unspecified user devices are connected to each other via, e.g., wireless communications. In this state, if the conventional digital authentication determines that a third party's device is determined to be “authentic”, and connection is established to that device, the user may sustain inadvertent damage by an ill-disposed user.
On the other hand, if the conventional digital authentication determines that a third party's device is “unauthentic” and that device is excluded, the advantages of ubiquitous networking as favors of a distributed process using other people's devices cannot be enjoyed.
That is, according to considerations of the present inventors, in a new type of network such as a ubiquitous network or the like, a new type of digital authentication, i.e., step-by-step and empirical authentication, is required in addition to the conventional alternative digital authentication.